How do brick and mortar shops stay in business?

Let's say you want to buy the Canon 16-35mm 2.8L Mk II. Why would you ever go to a store to pay (just quoted at my local shop) $1599.00 + 9% tax = $1750.00 when you can get it on line, at say B&H for 1420.00? Even with overnight shipping you still are paying, maybe 1450.00.